Personal Radiation Monitoring

Question 1

Why are staff monitored?

• Legal
• For Employer

Answer 1

Legal

• IRR17
• Risk assess all work with IR
• Local rules

For Employer to check:

• safe systems
• staff do not exceed limits

Question 2

Dose Limits (workers > 18)

Whole body

Extremity or skin

Lens of eye

Answer 2

• Whole body – 20mSv
• Extremity or skin – 500mSv
• Lens of eye – 20mSv

Question 3

When should somebody be classsified?

Answer 3

if an individual is ‘likely to receive an effective dose greater than 6mSv per year or an equivalent dose greater than 15mSv per year for the lens of the eye or greater than 150mSv per year for the skin or the extremities’ (IRR17 Reg 21)

Question 4

What things are the employer responsible for (relating to staff monitoring)

Answer 4

• Decide who and how to monitor
• supervise dosimeter wear, and return
• set local investigation levels
• perform audits
• keep records for 2 yeards
• responsible for non-classified doses
• work with other employers for classified workers
• Appoint ADS

Question 5

What things are the ADS responsible for (relating to staff monitoring)

Answer 5

• One or more of
  
  • Assessment of dose
  • record keeping
  • accident dosimetry
• Dosimetry assessments
• Classified worker’s record keeping

Question 6

Do all workers need an ADS?

Answer 6

Non-Classified - recommended that ADS supplies monitoring, employer is responsible for record keeping

Classified - MUST have ADS for monitoring and record keeping

Question 7

What is CIDI?

Answer 7

Health & Saftey Executive (HSE)’s Central index of Dose Information

• Hold dose data for all classified workers
• Updated by ADS

Question 8

User’s responsibilities

Answer 8

• Follow LR
• Always wear dosimeter, don’t take it home
• Return promptly
• Use PPE appropriately
• Don’t wear for own medical investigations
• Report incidents to RPS

Question 9

3 types of monitor

What do they measure?

Answer 9

1. Whole Body - Dose measured at a point on the body is used to estimate effective dose to whole body. Worn on trunk.
2. Finger - when body part is close to source. Estimates equivelent dose over 1cm^2 area
3. Lens - Equivelent dose over a 1cm^2 area

Question 10

What is personal dose equivelent Hp(d)?

Units?

How is it defined for whole body, extremity, eye?

Answer 10

Hp(d) is the equivelent dose at a depth d under the skin

mSv

Whole Body: 10mm

Extremity: 0.07mm

Eye: 3mm

Question 11

TLD

What is it used for?

Range?

Advantages?

Answer 11

Thermoluminescent dosimeter - Lithium fluoride (LiF)

Used for whole body & extrmity

1uGy - 10Gy

Re-usable

Question 12

OSL

What is it used for?

Range?

Advantages?

Answer 12

• Optically stimulated luminscence -
• Whole body & large extrmities
• 10uGy - 100Gy
• Can be re-read multiple times

Question 13

electronic devices

What is it used for?

Range?

Advantages?

disadvantages

Answer 13

• Whole body & Extremity
• Uses Si photodiodes, makes direct measurements of dose and dose rates
• used for potential high-dose situations e.g. for alarms in flouro
• expensive